html{
    background-image: url("pic2.jpg");
    background-repeat: no-repeat;
    background-size:  2000px 1000px;
}
body{
    width: 400px;
    /*margin: auto;*/
    padding: 1rem;
    text-align: center;
    border-radius: 10px;
    /*background-color: pink;*/

}

.btn{
    display: inline-block;
    border-radius: 8px;
    width: 70px;
    height: 50px;
}
.in{
    width: 260px;
    height: 30px;
}
#part2{
    flex-direction: column;
    display: flex;
    text-align: center;
    float:left;
    width:370px;
    /*height:500px;*/
    margin:10px;


}

.topnav {
    overflow: hidden;
    background-color: #333;

}

/* 导航链接 */
.topnav a {
    /* float: right; */
    margin: 0 auto;
    display: block;
    color: #f2f2f2;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

/* 链接 - 修改颜色 */
.topnav a:hover {
    background-color: #ddd;
    color: black;
}
/* 创建三个相等的列 */
.column {
    float: left;
    width: 33.33%;
}
tr {
    height: 2rem;
    text-align: center;
}

thead>tr {
    background-color: black;
    color: white;
}

tbody>tr:nth-child(odd) {
    background-color: white;
}

tbody>tr:nth-child(even) {
    background-color: white;
}

tbody>tr:hover {
    background-color: darkgray;
    color: white;
}

table,td,th
{
    border:1px solid black;
}
table
{
    /*width:100%;*/
    width: 1880px;
    border-spacing: 0;
}
th
{
    height:50px;
}
